近年来由于环境问题CO_2加氢制甲醇催化反应重新回归为研究热点。对于Pd/ZnO催化剂,研究表明PdZn合金相是制甲醇反应的活性中心,而单独Pd利于CO生成。为了实现Pd和ZnO的充分接触,本工作以一种ZnO@ZIF-8核壳型结构为载体负载Pd纳米颗粒...近年来由于环境问题CO_2加氢制甲醇催化反应重新回归为研究热点。对于Pd/ZnO催化剂,研究表明PdZn合金相是制甲醇反应的活性中心,而单独Pd利于CO生成。为了实现Pd和ZnO的充分接触,本工作以一种ZnO@ZIF-8核壳型结构为载体负载Pd纳米颗粒后经由高温煅烧制得PZZ8-T催化剂(T为不同煅烧温度),同时制备了ZnO纳米棒负载Pd的PZ催化剂作为对比。在随后的CO_2加氢反应中,相比于PZ,PZZ8-T展现出极高的甲醇选择性。之后我们通过一系列表征探究了催化剂的构效关系,发现催化剂的甲醇选择性与表面Pd的化学态有关,更多的Pd以PdZn合金的形式存在将会带来更高的甲醇选择性。XPS O 1s谱图和EPR分析表明CO_2的活化与催化剂表面的氧空穴和ZnO极性面含量直接相关。而化学吸附手段进一步对Pd-ZnO界面进行了表征,揭示了其与CO_2转化速率的关联。本工作的意义在于,一是展现了利用新材料制备更优的传统催化剂的方法,二是通过表面分析手段加深了对催化剂构效关系的理解。展开更多
导频污染是大规模MIMO(multiple-input and multiple-output)系统的瓶颈问题,提出一种联合用户位置和空间距离的导频分配方案来抑制导频污染。该方案首先将所有用户按到达角是否重叠进行分类,将到达角互不重叠的用户归为前n类集合,剩余...导频污染是大规模MIMO(multiple-input and multiple-output)系统的瓶颈问题,提出一种联合用户位置和空间距离的导频分配方案来抑制导频污染。该方案首先将所有用户按到达角是否重叠进行分类,将到达角互不重叠的用户归为前n类集合,剩余用户归为n+1类集合。为前n类用户集分配n组正交导频在集合内复用,而对n+1类集合中的用户进行导频选择时,定义一个干扰函数通过构建加权图的方式进行分配。同时,推导了上行频谱效率并分析了导频开销以及算法复杂度。仿真表明,该方案不仅减少了算法复杂度和导频开销,而且提高了系统的频谱效率(spectral efficiency,SE)。展开更多
Thermodynamic data were determined for the reversible binding of O 2 to two compounds of dicobalt(II) di(meso tetra phenyl)porphyrin derivatives with different lengths of diamidoaliphatic bridge (abbreviated to Co ...Thermodynamic data were determined for the reversible binding of O 2 to two compounds of dicobalt(II) di(meso tetra phenyl)porphyrin derivatives with different lengths of diamidoaliphatic bridge (abbreviated to Co 2PP 8 and Co 2PP 4) in N,N dimethylformamide at room temperature. The partial pressure of dioxygen necessary for half oxygenation ( P 1/2 ) and Hill coefficient ( n ) at 298 K were determined as follows: P 1/2 =54.2 kPa, n =2.0 for Co 2PP 8 and P 1/2 =6.8 kPa, n =1.8 for Co 2PP 4,respectively. The rate equations of reversible oxygen binding by Co 2PP 8 were determined and the reaction path was proposed. The results of thermodynamic and kinetic studies indicate that there exists strong cooperative effect during oxygenation of the compounds. The ESR observation reveals that the dioxygen complexes formed in the solutions are of superoxo (Co O - 2) type.展开更多
目的探讨2型糖尿病患者心率变异性(heart rate variability,HRV)与尿白蛋白/肌酐比值(albumin/creatinine ratio,ACR)的关系。方法选取上海交通大学医学院附属新华医院内分泌科住院的1543例2型糖尿病患者进行24 h动态心电图监测及ACR测...目的探讨2型糖尿病患者心率变异性(heart rate variability,HRV)与尿白蛋白/肌酐比值(albumin/creatinine ratio,ACR)的关系。方法选取上海交通大学医学院附属新华医院内分泌科住院的1543例2型糖尿病患者进行24 h动态心电图监测及ACR测定,HRV参数包括正常间隔到正常间隔的标准差(standard deviation of all normal to normal intervals,SDNN)、相临RR间期之差的均方根值(root mean square differences of successive RR intervals,rMSSD)、相邻RR间期相差>50 ms的数量占总心搏数的百分比(the percent of adjacent RR intervals with a difference greater than 50 ms,PNN50)、低频(low frequency,LF)、高频(high frequency,HF)、LF与HF的比值(LF/HF)。多元线性回归分析HRV与ACR的关系。将HRV参数分为≤25%(Q1)与≥25%(Q2~Q4)两组,分析其与白蛋白尿的关系。结果多元线性回归显示,HRV参数[ln(SDNN)、ln(PNN50)、ln(LF)、ln(HF)、ln(LF/HF)]减低与ln(ACR)的增加密切相关(均P<0.05)。Logistic回归分析显示,SDNN(OR=1.669,95%CI 1.290~2.159)、PNN50(OR=1.372,95%CI 1.063~1.770)、LF(OR=1.918,95%CI 1.441~2.551)、LF/HF(OR=1.623,95%CI 1.220~2.183)在Q1组发生白蛋白尿的风险较Q2~Q4组更高(均P<0.05);进一步按病程中位数(10年)、心血管疾病分层进行多因素logistic回归分析,在糖尿病病程≤10年或未合并心血管疾病患者中,SDNN和LF的Q1组有更高的发生白蛋白尿的风险,而在糖尿病病程>10年或合并心血管疾病患者中,SDNN、PNN50、LF和LF/HF的Q1组有更高的发生白蛋白尿的风险。结论2型糖尿病患者中HRV参数减低与ACR升高密切相关,且随着糖尿病的进展,HRV分析中有更多参数的减低增加白蛋白尿的发生风险。展开更多
Ionic liquids have many unique properties as a new and remarkable class of environmental benign solvents,which promises widespread applications in industry and other areas. However,the ionic liq-uids with surface acti...Ionic liquids have many unique properties as a new and remarkable class of environmental benign solvents,which promises widespread applications in industry and other areas. However,the ionic liq-uids with surface activity are rarely reported. In this work,a series of novel ionic liquids was synthe-sized by using N-methyl-2-pyrrolidone and alkyl bromide. The physical properties of this family of ionic liquids have been characterized,which shows that these compounds have ionic liquids characteristics,surface activity and biocompatibility.展开更多
Objective To explore the relationship between heart rate variability(HRV)and urine albumin/creatinine ratio(ACR)in patients with type 2 diabetes.Methods A total of 1543 patients with type 2 diabetes were selected from...Objective To explore the relationship between heart rate variability(HRV)and urine albumin/creatinine ratio(ACR)in patients with type 2 diabetes.Methods A total of 1543 patients with type 2 diabetes were selected from the Department of Endocrinology of Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine,and all the participants received 24-hour Holter monitoring and ACR measurement.展开更多
基金supported by the National Science Foundation of China(21373153)~~
文摘近年来由于环境问题CO_2加氢制甲醇催化反应重新回归为研究热点。对于Pd/ZnO催化剂,研究表明PdZn合金相是制甲醇反应的活性中心,而单独Pd利于CO生成。为了实现Pd和ZnO的充分接触,本工作以一种ZnO@ZIF-8核壳型结构为载体负载Pd纳米颗粒后经由高温煅烧制得PZZ8-T催化剂(T为不同煅烧温度),同时制备了ZnO纳米棒负载Pd的PZ催化剂作为对比。在随后的CO_2加氢反应中,相比于PZ,PZZ8-T展现出极高的甲醇选择性。之后我们通过一系列表征探究了催化剂的构效关系,发现催化剂的甲醇选择性与表面Pd的化学态有关,更多的Pd以PdZn合金的形式存在将会带来更高的甲醇选择性。XPS O 1s谱图和EPR分析表明CO_2的活化与催化剂表面的氧空穴和ZnO极性面含量直接相关。而化学吸附手段进一步对Pd-ZnO界面进行了表征,揭示了其与CO_2转化速率的关联。本工作的意义在于,一是展现了利用新材料制备更优的传统催化剂的方法,二是通过表面分析手段加深了对催化剂构效关系的理解。
文摘导频污染是大规模MIMO(multiple-input and multiple-output)系统的瓶颈问题,提出一种联合用户位置和空间距离的导频分配方案来抑制导频污染。该方案首先将所有用户按到达角是否重叠进行分类,将到达角互不重叠的用户归为前n类集合,剩余用户归为n+1类集合。为前n类用户集分配n组正交导频在集合内复用,而对n+1类集合中的用户进行导频选择时,定义一个干扰函数通过构建加权图的方式进行分配。同时,推导了上行频谱效率并分析了导频开销以及算法复杂度。仿真表明,该方案不仅减少了算法复杂度和导频开销,而且提高了系统的频谱效率(spectral efficiency,SE)。
文摘Thermodynamic data were determined for the reversible binding of O 2 to two compounds of dicobalt(II) di(meso tetra phenyl)porphyrin derivatives with different lengths of diamidoaliphatic bridge (abbreviated to Co 2PP 8 and Co 2PP 4) in N,N dimethylformamide at room temperature. The partial pressure of dioxygen necessary for half oxygenation ( P 1/2 ) and Hill coefficient ( n ) at 298 K were determined as follows: P 1/2 =54.2 kPa, n =2.0 for Co 2PP 8 and P 1/2 =6.8 kPa, n =1.8 for Co 2PP 4,respectively. The rate equations of reversible oxygen binding by Co 2PP 8 were determined and the reaction path was proposed. The results of thermodynamic and kinetic studies indicate that there exists strong cooperative effect during oxygenation of the compounds. The ESR observation reveals that the dioxygen complexes formed in the solutions are of superoxo (Co O - 2) type.
文摘目的探讨2型糖尿病患者心率变异性(heart rate variability,HRV)与尿白蛋白/肌酐比值(albumin/creatinine ratio,ACR)的关系。方法选取上海交通大学医学院附属新华医院内分泌科住院的1543例2型糖尿病患者进行24 h动态心电图监测及ACR测定,HRV参数包括正常间隔到正常间隔的标准差(standard deviation of all normal to normal intervals,SDNN)、相临RR间期之差的均方根值(root mean square differences of successive RR intervals,rMSSD)、相邻RR间期相差>50 ms的数量占总心搏数的百分比(the percent of adjacent RR intervals with a difference greater than 50 ms,PNN50)、低频(low frequency,LF)、高频(high frequency,HF)、LF与HF的比值(LF/HF)。多元线性回归分析HRV与ACR的关系。将HRV参数分为≤25%(Q1)与≥25%(Q2~Q4)两组,分析其与白蛋白尿的关系。结果多元线性回归显示,HRV参数[ln(SDNN)、ln(PNN50)、ln(LF)、ln(HF)、ln(LF/HF)]减低与ln(ACR)的增加密切相关(均P<0.05)。Logistic回归分析显示,SDNN(OR=1.669,95%CI 1.290~2.159)、PNN50(OR=1.372,95%CI 1.063~1.770)、LF(OR=1.918,95%CI 1.441~2.551)、LF/HF(OR=1.623,95%CI 1.220~2.183)在Q1组发生白蛋白尿的风险较Q2~Q4组更高(均P<0.05);进一步按病程中位数(10年)、心血管疾病分层进行多因素logistic回归分析,在糖尿病病程≤10年或未合并心血管疾病患者中,SDNN和LF的Q1组有更高的发生白蛋白尿的风险,而在糖尿病病程>10年或合并心血管疾病患者中,SDNN、PNN50、LF和LF/HF的Q1组有更高的发生白蛋白尿的风险。结论2型糖尿病患者中HRV参数减低与ACR升高密切相关,且随着糖尿病的进展,HRV分析中有更多参数的减低增加白蛋白尿的发生风险。
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20233010 and 20573079)
文摘Ionic liquids have many unique properties as a new and remarkable class of environmental benign solvents,which promises widespread applications in industry and other areas. However,the ionic liq-uids with surface activity are rarely reported. In this work,a series of novel ionic liquids was synthe-sized by using N-methyl-2-pyrrolidone and alkyl bromide. The physical properties of this family of ionic liquids have been characterized,which shows that these compounds have ionic liquids characteristics,surface activity and biocompatibility.
文摘Objective To explore the relationship between heart rate variability(HRV)and urine albumin/creatinine ratio(ACR)in patients with type 2 diabetes.Methods A total of 1543 patients with type 2 diabetes were selected from the Department of Endocrinology of Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine,and all the participants received 24-hour Holter monitoring and ACR measurement.
